Program controlled stirrer and method for the operation thereof

ABSTRACT

The invention relates to a program controlled stirrer for producing pharmaceutical or cosmetic recipes, comprising a stirring unit which consists of a stirring tool which engages with a mixing receptacle. According to the invention, the stirring unit is coupled to a micro-processor which determines the length of stirring time and stirring speed at the stirring unit in a program-controlled manner. The micro-processor executes a data-processing program with the following steps: input of variable data; input of constant data; determination of the length of stirring time and stirring speed in order to produce the desired amount of the recipe by combining the variable and constant data; conversion of the determined length of stirring time and stirring speed into corresponding first current or voltage values; control of the stirring unit with said first current or voltage values. Preferably, the size of the receptacle is inputted as variable data, whereby the data-processing program calculates the number of necessary rotations of the stirring tool using the constant data stored in the data memory, then controls the stirring unit correspondingly.

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] This invention relates to a method for the use of a programcontrolled stirrer for producing pharmaceutical or cosmetic recipes orthe like, comprising an electric stirring unit whose revolutions can becontrolled, consisting of a stirring unit which reaches into a mixingreceptacle, whereby the stirring unit is coupled to a micro-processorwhich determines the length of stirring time and stirring speed at thestirring unit in a program-controlled manner.

[0002] For example, for pharmaceutical or cosmetic medicalprescriptions, one step recipes are produced from ointments, powdermixtures, gels and the like. In the singular preparation of suchrecipes, which usually takes place in pharmacies, the components of therecipe are manually mixed using traditional methods. To do this, mortarand pestle as well as glass plate and spatula can be used. In additionto the risk of contamination to the substances being produced due to themanual procedure, there is also the problem that the conditions in whichthe mixing of the single substances is carried out are not reproducibleand documentable. Thus in the repeated production of the same recipesignificant quality differences may result, which could affect theeffectiveness of the recipe.

[0003] A device for stirring, mixing, chopping or the like is known fromDE 196 41 972 C2. Such a device (which can be referred to as stirrer)features a stirring unit and a lifting unit to mix certain substancestogether using a stirring tool in a mixing container in a partlyautomatic manner so as to obtain the desired recipe as a result. Withthis device, according to the state of the art, it is possible to changethe stirring speed, the stirring time, the stroke rate and the liftingspeed within set limits so as to adjust them to special types ofrecipes. These parameters of the stirrer must be adjusted to thecharacteristics of the initial substances as well as to the relevantamount of these substances for the result from the mixing process to besatisfactory. The disadvantage of this known device lies in that theoptimal parameters of the different mixing processes do not remainavailable for a long period of time and therefore must constantly bere-input. Individual inputs of mixing time, number of revolutions perminute of the stirrer, lifting speed and stroke rate are notreproducible at a later point in time. Thus, special recipes, both inthe case of their production by different pharmacies and in the repeatedproduction by the same pharmacy at different points in time, can havehighly variable qualities. In this way, for the same medicalprescription a quality uniformity (Good Manufacturing Practice—GMP)cannot be assured.

[0004] DE 39 19 534 A1 shows a method and a piece of equipment for thepreparation of bone cement. According to this method, an automaticprocess command is provided so that the mixing phase and/or the restphase are selected in consideration of the relevant type of bone cementand the amount of it being used. The operation of the described piece ofequipment is, however, relatively costly because the control parametersmust be manually input. Moreover, the documentation of the mixturesobtained is not assured and therefore the repeatability for identicalmixtures cannot be guaranteed.

[0005] A method for the control of stirring processes is known from DE31 26 552 A1. Based on the viscosity of a substance, the optimum powerinput of the stirrer is adjusted. Additionally, the viscosity can becontinuously set during the stirring process. Repeatable, documentableand fast production of mixtures from the automatic use of the parametersbased on container size is therefore not achieved.

[0006] Finally, DE 43 02 085 C1 reports on a method for the dosing andmixing of dental filling substances made up of several components and onthe piece of equipment for the application of the method.

[0007] One task of this invention is to minimize quality differences inthe production of individual ointment recipes. An additional task liesin facilitating the use of stirrers so that cosmetic and pharmaceuticalproducts can be produced with the desired quality even by less qualifiedpersonnel. Moreover, the invention must allow for the production ofindividual recipes resulting in equal quality that are produced withlong time intervals between productions and enable an increase ineffectiveness in the repeated production of such recipes.

[0008] These and other problems are solved by a method which includesthe following steps:

[0009] Input of variable data into data input devices which define atleast:

[0010] the amount and the category of the recipe to be produced within agiven tolerance range and,

[0011] the size of the mixing receptacle;

[0012] Input of nonvariable data from a data memory which, for presetcategories of recipes and sizes of mixing receptacles, contains thebasic values for the stirring time and stirring speed;

[0013] Determination of the length of stirring time and stirring speedin order to produce the desired amount of the recipe by combining thevariable and nonvariable data;

[0014] Conversion of the determined length of stirring time and stirringspeed into corresponding initial current or voltage values and controlof the stirring unit with these control parameters;

[0015] Storage of the control parameters adopted during the productionof the recipe, together with identification data in a data memory;

[0016] Output of the control parameters and/or identification dataadopted, through a data output device, in electronic and/or printedform.

[0017] The main advantage of the stirrer according to the invention liesin that a GMP-compliant quality uniformity of the recipes to be producedcan widely be assured. It is guaranteed that the same recipe will beproduced using the same mixing conditions. Moreover, errors in the useof the stirrer are widely prevented.

[0018] An advantageous embodiment of the program controlled stirrer alsoincludes a lifting unit, through which the relative position of thestirring tool in the mixing receptacle can be changed during thestirring process, whereby the data-processing program executed by themicro-processor includes the following steps:

[0019] Determination of the necessary stroke rate and lifting speed inorder to produce the desired quality of the recipe by combining thevariable and nonvariable data;

[0020] Conversion of the determined stroke rate and lifting speed intocorresponding initial current or voltage values;

[0021] Control of the lifting unit with said initial current or voltagevalues.

[0022] The inclusion of the lifting unit in the control through themicro-processor further increases the quality uniformity required by theMedicines Act. Moreover, in this way it is also possible to adjust thestirring mode to the special initial substances and the desired endproduct. At this point it must be specified that in this context theword “stirring” also refers to the chopping of the initial substances,the mixing and blending of the initial substances as well as any otherkind of preparation that can be performed by the stirring tool in themixing receptacle.

[0023] By using the program controlled stirrer, ointments, gels andother pasty masses can be produced. Besides, single powdery substancescan be blended together if this is necessary for a certain recipe.Different stirring tools can be fitted, which in size and shape areadjusted to both the mixing receptacle and the mixing task to befulfilled.

[0024] According to a practical embodiment, variable data on theviscosity of the initial substances is input through the data inputdevices. If required, additional data describing the substances orguideline values concerning the stirring time, the stirring speed, thestroke rate and the lifting speed can also be input. When usingguideline values, the program controlled stirrer compares theseguideline values with the minimum values stored in the data memory andadopts these minimum values if the guideline values are below theminimum values. In this way a seriously incorrect condition of thestirrer is avoided because a minim quality of the relevant recipe isguaranteed by the application of the minimum values. In another modifiedembodiment it is also possible to compare the guideline values withmaximal values stored in the data memory.

[0025] A particularly preferred embodiment of the stirrer enables thestorage of the control parameters adopted during the production of therecipe, i.e. either the stirring time, the stirring speed, the strokerate and the lifting speed or the current or voltage values beingutilized to command the stirring unit and/or the lifting unit. This datais combined with the individualizing data so that, at a later point intime, the special control parameters adopted can be tracked back throughthe individualizing data, should an identical recipe be produced again.As another advantage, this measure also brings about a significant timesaving because the control parameters for the stirrer must be input onlyonce and can be quickly called up from the data memory for a laterproduction of the same type of recipe.

[0026] In another enhanced embodiment of the program controlled stirrer,an output unit is also provided, through which the control parameters tobe adopted and, if required, also the identification data, can beoutput. For example, the identification data can be printed on a labelthat can be put on the packaging of the produced recipe. In this way,the identification data is available when a new order of the same recipeis made with the used packaging unit.

[0027] Obviously the output of the data in electronic form is alsopossible. In other embodiments, the data can be coded in a bar code sothat all of the control parameters can be input with a scanner. Thiswould also allow for standardization of the production in differentpharmacies, seeing that not only the identification data but also theentire control data set can be encoded in a bar code.

[0028] When the program controlled stirrer is assembled as a stand alonedevice, a keyboard, a touch screen or a similar data input device isprovided in order to store the variable data. In a modified embodiment,a PC is fitted with a data connection available for data input and alsofor data storage. The data connection, for example, can be made througha serial interface. This is particularly advantageous because in thisway traditional computers can be used which are equipped with a specialcontrol program.

BRIEF DESCRIPTION OF THE FIGURES

[0029] Other advantages, details and further developments emerge fromthe following description of a preferred embodiment, with reference tothe drawings. These show:

[0030]FIG. 1 a block circuit diagram of a program controlled stirrer;

[0031]FIG. 2 a flow-chart of the information of the stirrer during themixing process.

DETAILED DESCRIPTION

[0032]FIG. 1 shows a simplified block circuit diagram of a preferredembodiment of a program controlled stirrer. The actual stirring deviceconsists of a stirring unit 1 and a lifting unit 2. Through these twounits, a stirring tool is driven, which works in combination with amixing receptacle. The stirring tool is adjusted to the size of themixing receptacle to reach an optimum stirring result. Preferably thestirring tool can be changed, for example when different sizes of mixingreceptacles are used. Stirring tool 1 and lifting unit 2 work incombination with each other in such a way that the stirring tool rotatesin the mixing receptacle and the relative position between the stirringtool and the mixing receptacle changes so that the stirring unit canproperly mix all the areas inside the mixing receptacle. Therefore, itis possible to change the stirring tool in its vertical position andalso to obtain the vertical movement by sliding the mixing receptaclewith the stirring tool in fixed position.

[0033] The program controlled stirrer also features a micro-processor 5,which acquires the control of the stirring unit 1 and lifting unit 2.The microprocessor 5 executes a data-processing program, whose singleprocess steps are illustrated in detail below. The control data suppliedby the micro-processor 5 for the stirring unit 1 and the lifting unit 2is converted into current or voltage values in a conventional manner,using known circuit elements (not shown). The micro-processor 5 canaccess a data memory 7 in order to load pre-set nonvariable data and/orstore determined control data for a later mixing process. Furthermore,the micro-processor 5 works in combination with data input devices 8 anddata output devices 9. Through data input 8, variable data can be inputby the user. In particular, the user can set the amount of the recipe tobe produced (for example a suspension ointment), the desired stirringtime and the desired number of revolutions of the stirring tool. Toachieve this objective, there is the opportunity to input the size ofthe mixing receptacle used so as to determine the optimum control valuesfor the stirrer from this input. The micro-processor 5 combines thevariable data input through the data input devices 8 with thenonvariable data that is stored in the data memory 7. The variable datais compared with minimum values and maximum values, which indicate thelimit values allowed for the stirring speed, the stirring time, thelifting speed and the stroke rate.

[0034] It should be pointed out that the stirring process must not becarried out with nonvariable control values for the entire time. Withcertain substances it is appropriate to start with a low stirring speedand then proceed with a higher number of revolutions of the stirringtool to reach an optimum mixing result. After a so-called gratingprocess, the number of revolutions of the stirring tool can be increasedto produce an even mixture as quickly as possible.

[0035] The microprocessor 5 can output the control parameters usedthrough the data output devices 9. The data output devices 9 can includea display indicating both the present operational status and the controlparameters to be used during the mixing process. Moreover, a printer oran external data memory can be assigned to the data output devices 9 inorder to store the control parameters in printed form, for example onthe label of the recipe produced or on external electronic data memoriesfor a later use.

[0036]FIG. 2 shows a sequence of information from a reporting unit ofthe data output device during a mixing process performed by a programcontrolled stirrer. Based on this sequence, the essential steps executedby the program controlled stirrer, in which the control of these processsteps is obtained through the data-processing program executed by themicroprocessor are illustrated below.

[0037] In the illustrated example, a suspension ointment is to beproduced in an amount of 50 ml. Step 10 reports the indication of whenthe data input is to be finished. First, the stirrer is put into serviceand the necessary data is input by the user through the data inputdevices in step 11. At a minimum the quantity of the suspension ointmentto be produced is to be input, with the possibility of inputtingadditional optional data like, for example, the desired duration of thestirring process. Based on the data stored in the data memory, thedata-processing program is able to independently determine all the otherdata right from the input amount of the recipe to be produced. In thiscase, stored guideline values for the stirring time, the stirring speed,the lifting speed and the stroke rate are used. The guideline values canbe input by the manufacturer of the program controlled stirrerpermanently into the data memory. There is also the possibility for theuser to store the guideline values in a programming mode if this seemssuitable for certain application cases. Moreover, the recipe number and,if available, a batch mark can be input or can be provided by thedata-processing program. Such data is used as identification data, whichenables a univocal classification of the mixing process performedaccording to the control parameters used. In the batch marking, allfundamental data is coded, for example the type of recipe (normal type,emulsion, suspension, reaction mix, powder or the like) and specialinstructions on the stirring process (for ex., with grating process whenusing suspensions).

[0038] When all guideline data has been input and the missing datanecessary for a control of the mixing process has been determined by thedata-processing program in step 12, the mixing process begins. In theexample shown, the mixing process begins with the grating process thatalso in the batch marking is identified as “AR”. Step 20 illustrates theindication that appears during the grating process. The rotation speed,which is adjusted to the special type of products to be produced is alsoreported. In this case the speed is 1,000 revolutions per minute (rpm).Furthermore, the number of revolutions and the stroke rate as well asthe remaining mixing time are input.

[0039] After the conclusion of the grating process, the “normal” mixingprocess begins and the display changes to the status illustrated in step30. Also here, the present rotation speed, the number of the revolutionsto be executed, the stroke rate of the stirrer and the remaining timefor the present mixing process are reported. Parallel to theseindications, the control parameters adopted in step 31 are stored and/oroutput, for example decoded in the identification data printed on alabel. After the conclusion of the mixing process, the display goes backto step 10 so that the user can control the correct completion of therecipe also from the display. Obviously, it is also possible to generatea modified conclusion report with which the user is informed of thesuccessful completion of the mixing process in a summarized form.

[0040] In an adjusted embodiment a final fast homogenizing process canbe carried out after an initial mixing phase. In this way, the totaltime of production of the recipe can be significantly shortened.

[0041] It is also useful to document the number of mixing processesexecuted and the resulting operation time of the stirrer in the datamemory and have it available for maintenance. In this way, the user canbe informed at the right time that the stirrer requires maintenance,thereby following recommended maintenance intervals, so that the life ofthe stirrer is increased and its functional safety is guaranteed.

[0042] Since a stirrer is preferably equipped with specially preparedmixing receptacles, a preprogrammed number of revolutions that themixing tool must execute can be set for the various mixing receptaclesizes. The user must simply enter and save the receptacle sizes throughthe data input devices.

[0043] In a modified embodiment, sensors are installed whichautomatically detect the size of the receptacle so that input of thisdata occurs automatically without any direct action by the user.

1. Method for the use of a program controlled stirrer for producing pharmaceutical or cosmetic recipes or the like, comprising an electric stirring unit whose revolutions can be controlled (1), which consists of a stirring tool reaching into a mixing receptacle, whereby the stirring unit is coupled to a micro-processor (5) which determines the length of stirring time and stirring speed at the stirring unit (1) in a program-controlled manner, whereby the method includes the following steps: Input (11) of variable data into data input devices (8), which define at least the amount and the category of the recipe to be produced within a given tolerance range and, the size of the mixing receptacle; Input (11) of nonvariable data from a data memory (7) which, for preset categories of recipes and sizes of mixing receptacles, contains the basic values for the stirring time and stirring speed; Determination (12) of the length of stirring time and stirring speed in order to produce the desired amount of the recipe by combining the variable and nonvariable data; Conversion of the determined length of stirring time and stirring speed into corresponding initial current or voltage values and control of the stirring unit with these control parameters; Storage of the control parameters adopted during the production of the recipe, together with identification data in a data memory (7); Output of the control parameters and/or identification data adopted, through a data output device (9), in electronic and/or printed form.
 2. Method according to claim 1, whereby the program controlled stirrer also includes a lifting unit (2), through which the relative position of the stirring tool in the mixing receptacle can be changed during the stirring process, and whereby the method includes the following steps: Determination of the optimum stroke rate and lifting speed in order to produce the desired quality of the recipe by combining the variable and nonvariable data; Conversion of the determined stroke rate and lifting speed into corresponding second current or voltage values; Control of the lifting unit with said second current or voltage values.
 3. Method according to claim 1 or 2, also including a step using the variable and nonvariable data to determine of the number of the necessary revolutions for the stirring tool.
 4. Method according to one of the claims from 1 to 3, also including the step of the input of the viscosity of the initial substances as variable data.
 5. Method according to one of the claims from 2 to 4, also including the following steps: Loading of guideline values for stirring time, stirring speed, stroke rate and lifting speed as additional variable data; Comparison of these guideline values with preset minimum values, which are also stored in the data memory; Application of the minimum values for stirring time, stirring speed, stroke rate and lifting speed when the guidelines values are below the minimum values.
 6. Method according to one of the claims from 2 to 5, also including the step of storing the maximum stirring time, stirring speed, stroke rate and lifting speed of the stirrer depending on the amount and viscosity of the various initial substances in the data memory (7).
 7. Method according to claim 1, also including the following steps: Encoding all the control parameters and/or identification data in a bar code; Output of the encoded control parameters by printing them on a label of the packaging of the produced recipe.
 8. Method according to claim 1, also including the following step: Input of a recipe identification as variable data; Input of the control parameters, whose identification data corresponds to the recipe identification, from the data memory; Use of the stored control parameters to the control of the stirring unit and the lifting unit; so that the new recipe can be produced with the same parameters as a recipe that had been produced at an earlier point in time.
 9. Method according to one of the claims from 1 to 8, in which input of the variable data is executed through a personal computer having a data connection with the stirrer, and whereby storing of the control parameters is executed in a data memory (7) available on this personal computer
 10. Method according to one of the claims from 1 to 9, also including the step of the automatic determination of the size of the mixing receptacle and/or the amount of the initial substances with the aid of sensors. 